The present invention relates to the development and use of a novel bacterial system based protocol to screen the efficacy of the chemical compounds for Ultraviolet radiation protection. Preferably, the invention relates to a new use of the compound menthyl benzoate suitable for providing protection against the harmful effects of ultraviolet radiation. The invention also extends to identifying the quantum of protection provided by menthyl benzoate, which is much higher than the known UV protectants like dibenzoyl methane and benzyl benzoate.
The exposure to sunlight can pose a variety of damages to the skin and the damaging effects may result in hazardous effects like sunburn which primarily result from exposure to UVB radiation within the sunlight spectrum having a wavelength of about 290 to 320 nm. But continuous exposure over the long run may also lead to malignant cancerous cells on the skin surface. Studies have demonstrated a strong relationship between sunlight exposure and human skin cancer. Other hazards of ultra violet radiation exposure include premature aging of the skin, which is primarily caused by the UVA radiation having a wavelength of from about 320 nm to about 400 nm. This condition is characterized by wrinkling and pigments changes of the skin, along with other physical changes such as cracking, telangiectasis, solar dermatoses, ecchymoses, and loss of elasticity etc.
Due to the rising incidence and awareness about the hazards of sun exposure with the realization of ozone layer depletion due to green house gases in the atmosphere, many compounds and compositions have been appearing in the market and the prior arts are full of such compositions for cosmetic and personal care products. But most of the sunscreen products, in particular do not provide sufficient protection against broad spectrum UV radiations, i.e., protection against both UVB and UVA wavelength ranges. Mostly the commercially available sunscreen products absorb UV radiation in the wavelengt range of 290 nm to 320 nm (UVB domain) protecting against the sunburn. Their ineffectiveness in the 320 nm to 400 range (UVA domain) leaves the skin vulnerable to premature aging and wrinkling. General lack of UVA absorbing sunscreen actives or UV sieve compounds is conspicuous among the products, which are both commercially available and also approved for global use.
One class of the available sunscreen actives includes dibenzoylmethane compounds which provide broad-spectrum UV protection such as 4-tert-butyl-4xe2x80x2-methoxydibenzoylmethane. Unfortunately, these sunscreens tend to photodegrade upon exposure to UV radiation thereby reducing their UVA efficacy. Consequently, sunscreen products, which include these compounds, are typically difficult to formulate due to the inherent lack of photostability of dibenzoylmethane compounds. Further, modification of these chemicals may be hazardous to the skin or make them environmentally unsafe. From plant sources, the compounds known to be safe for human use can be screened isolated and modified for use as sunscreen. Sunlight is required for health, and a sunscreen composition absorbing 100% of the sunlight is not desirable. The desirable feature is that the damaging wavelength range of sunlight spectrum should be reduced to the safe threshold level which is skin and tissue safe by using the compounds which are harmless to the biological system.
Thus, there is a need for screening compounds from diverse sources, which can be used in compositions suitable for providing protection against the harmful effects of UV radiation to human skin. In particular, in the personal care products industry, there is a rising need for sunscreen products possessing excellent photostability, efficiency with the capability to provide broad-spectrum UV protection (i.e., against both UVA and UVB radiation) in a safe and economical manner.
With these rationale in mind the applicants constructed a bacterial model system and a method to use the system in rapid large scale screening of compounds which can protect the cells against UV damage (312 nm to 365nm) either in form of a sieve or in vicinity of target cells. A variety of compounds including several monoterpenes and their derivatives were screened using the known protectant Benzyl benzoate and Dibenzoyl methane as control molecules. The procedure is rapid, novel, most convenient and environmentally compatible not requiring human or animal subject and/or complexities of cell culture in skin testing. Results can be obtained overnight and are 100% interpretable as evident from the control compounds and additionally provide quantifiable data on extent of protection. In this screening approach which itself was the objective of the invention menthyl benzoate was found to provide significant protection with excellent efficiency for both UV radiation (UVA and UVB) and hence, making its use as UV protectant evident.
The main object of the invention relates to a new alternative and quick protocol to screen large number of compounds for UV protection. This was achieved by testing the known UV protectants as well as a known compound not formerly for UV protection.
Another object of the invention relates to providing a compound which can be used for protecting biological systems from UV light.
Yet another object of the invention relates to providing a biologically safe compound which can be used as a UV protectant for biological systems.